Astronomers from Rice University and China's Sun Yat-sen University say their head-on impact scenario can explain Juno's previously puzzling gravitational readings, which suggest that Jupiter's core is less dense and more extended that expected.
"This is puzzling," said Rice astronomer and study co-author Andrea Isella. "It suggests that something happened that stirred up the core, and that's where the giant impact comes into play."
Isella said leading theories of planet formation suggest Jupiter began as a dense, rocky or icy planet that later gathered its thick atmosphere from the primordial disk of gas and dust that birthed our sun.
Comment: It's worth noting that leading theories of planetary formation are up for question: Observations of young stars are overturning theories of planet formation
Isella said he was skeptical when study lead author Shang-Fei Liu first suggested the idea that the data could be explained by a giant impact that stirred Jupiter's core, mixing the dense contents of its core with less dense layers above. Liu, a former postdoctoral researcher in Isella's group, is now a member of the faculty at Sun Yat-sen in Zhuhai, China.
"It sounded very unlikely to me," Isella recalled, "like a one-in-a-trillion probability. But Shang-Fei convinced me, by shear calculation, that this was not so improbable."
The research team ran thousands of computer simulations and found that a fast-growing Jupiter can have perturbed the orbits of nearby "planetary embryos," protoplanets that were in the early stages of planet formation.
Liu said the calculations included estimates of the probability of collisions under different scenarios and distribution of impact angles. In all cases, Liu and colleagues found there was at least a 40% chance that Jupiter would swallow a planetary embryo within its first few million years. In addition, Jupiter mass-produced "strong gravitational focusing" that made head-on collisions more common than grazing ones.
Isella said the collision scenario became even more compelling after Liu ran 3-D computer models that showed how a collision would affect Jupiter's core.
"Because it's dense, and it comes in with a lot of energy, the impactor would be like a bullet that goes through the atmosphere and hits the core head-on," Isella said. "Before impact, you have a very dense core, surrounded by atmosphere. The head-on impact spreads things out, diluting the core."
Impacts at a grazing angle could result in the impacting planet becoming gravitationally trapped and gradually sinking into Jupiter's core, and Liu said smaller planetary embryos about as massive as Earth would disintegrate in Jupiter's thick atmosphere.
"The only scenario that resulted in a core-density profile similar to what Juno measures today is a head-on impact with a planetary embryo about 10 times more massive than Earth," Liu said.
Isella said the calculations suggest that even if this impact happened 4.5 billion years ago, "it could still take many, many billions of years for the heavy material to settle back down into a dense core under the circumstances suggested by the paper."
Isella, who is also a co-investigator on the Rice-based, NASA-funded CLEVER Planets project, said the study's implications reach beyond our solar system.
"There are astronomical observations of stars that might be explained by this kind of event," he said.
"This is still a new field, so the results are far from solid, but as some people have been looking for planets around distant stars, they sometimes see infrared emissions that disappear after a few years," Isella said. "One idea is that if you are looking at a star as two rocky planets collide head-on and shatter, you could create a cloud of dust that absorbs stellar light and reemits it. So, you kind of see a flash, in the sense that now you have this cloud of dust that emits light. And then after some time, the dust dissipates and that emission goes away."
The Juno mission was designed to help scientists better understand Jupiter's origin and evolution. The spacecraft, which launched in 2011, carries instruments to map Jupiter's gravitational and magnetic fields and probe the planet's deep, internal structure.
Additional co-authors of the study include Yasunori Hori of the Astrobiology Center of Japan, Simon Müller and Ravit Helled of the University of Zurich, Xiaochen Zheng of Tsinghua University in Beijing and Doug Lin of both the University of California, Santa Cruz, and Tsinghua University in Beijing.
That mythological archetypes are the structural basis of our consciousness is no less the result of a 'charge event' or split mind.
I hold the time scale of modern Cosmology open as I do of the very nature and notion of time. Perhaps what we accept as linear time is an equilibrium within a domain that from the point of view of continuity, can only be looked upon as a punctuation.
As it happens the apostrophe is associated with Venus and catastrophe.
Convergences of 'archetypal' origins have BOTH psychic and physical aspects.
A psycho-physical Universe is NOT subjectivism - or a split off 'mind' but a truly Open Creation.
The subjected mind assigns CAUSE to externality - and yet the assignation of EXTERNALITY is already a projective definition as 'outside a realm of personal control or private possession'.
Sketching an integrative consciousness is toward the release of impact or attack theology.
Baffled boffins head scratching without anything but increasing absurd conjecture run computer models in search of plausible support for evidences that otherwise cannot be accepted because they speak directly from beyond the domain or premises of a defining sense of narrative or reality 'control'.
This itself reveals that our interpretation or meaning GIVEN to our relational being creates our perception-experience and response. And in larger terms, our corporate technologism springs forth from it fully armed and armoured. Pallas Athena or Spear shaker.
The Period is a defining parameter to the point of focus and its unfolded meaning. Myth is simply story and narrative identity is the structural basis FOR the unfolding of storied meaning or dramatic representation as a physical explicate of implicit qualities.
The distantiation of the Creative unto millions or billions of years is a psychic need for the experience of creation (being or existence) as destructive (pain of loss in conflict and disconnection or death as loss of face and power).
The idea that power can be persona-fied or possessed and wielded is the idea of chaos and control where chaos represents from the denial or non acceptance of what is, while control seeks sustainability as a sense of possession and control. These two are one, and yet operate psychic-emotionally as forever set each the opposite and exclusion of the other.
Computer models or any other modelling modality can only result the input parameters. Imagination set free of the split mind of marketisation and weaponisation naturally opens integrative perspectives that embrace and transcend polarised identification. This is the resonantly informing field of energetic exchange that is hidden, filtered or blocked by the densities of action-reaction which pertain to a tiny percentage of the physical Universal Expression.
Focusing or specialisation inherently excludes. Over specialisation isolates and becomes spun out as its own derivative meanings of subjective distortion of an original 'object of affection' or resonant recognition that can be called 'Know Thyself' or Self Aware - as distinct from self conscious division, conflict and inhibition or paralysis - in which time can seem to slow such as to become vast and impenetrable to a fleeting spark of almost waking that already fades to the structured containment of a dead safety - endlessly punctuated and repeating.
Yet in any spark is the Whole Universe expressed.